Oral care compositions for promoting gum health

ABSTRACT

Oral care compositions comprising citrulline and stannous ion source with a specific pH range are provided for promoting Gum Health of a user.

FIELD OF THE INVENTION

The present invention relates to oral care compositions comprisingstannous ion source and citrulline at a specific pH range for promotingGum Health of a user. In particular, such oral care compositions areuseful for improving gingival wound healing and improving the reductionof bacterial activity in the oral cavity of the user.

BACKGROUND OF THE INVENTION

Gum disease, such as gingivitis and/or periodontitis, gives rise toacute and chronic gum inflammation in the oral cavity. “Gingivitis” isthe milder form of the disease. Symptoms of gingivitis may include:gingival bleeding; and redness, swollen, or tender gums. If leftuntreated, gingivitis can advance to “periodontitis”. Withperiodontitis, gums pull away from the teeth and form spaces called “periodontal pockets” that can become infected by pathogenic bacteria.The bacteria are present on the tooth root surfaces as biofilms. Thebacteria in the biofilms can attack the gingival and underlying alveolarbone supporting teeth. These attacks can cause major damage to the softtissue and bone that support teeth. In the later stage of gum disease(i.e., “advanced periodontitis”), more serious problems of loosening ofteeth and eventual tooth loss can occur.

Some commercially available oral care compositions aim, principally, atalleviating one or more symptoms of the earlier stage of gum disease(i.e., gingivitis), which includes: relief of red, swollen, or tendergums; and/or stem gum bleeding. Typically, these compositions claimbenefits such as, “gum care”, “oral care”, “oral health”, “dental care,”or “dental health” to users. An example of such a composition is“Colgate® Total” toothpaste, which they claim to “help reduce the firststage of gum disease”, which is defined as “gingivitis, or bleedinggums” (seehttp://www.colgatetotal.com/total-benefits/whole-mouth-health/gingivitis-control).To help distinguish the benefits of the commercially available oral carecompositions versus the present invention, the inventors herein refer tothe aforementioned benefits of these commercially available oral carecompositions collectively as “Gum Care”. This is because thesecommercially available oral care compositions have been formulatedprimarily to care for the gums and relieve the symptoms (e.g., gumbleeding; and/or redness, swelling, or tender gums) associated with theearlier stage of gum disease (i.e., gingivitis).

However, there is a need to provide overall “Gum Health” benefits, whichas used herein, is a broader term and is intended to encompass at leastsome of the aforementioned Gum Care benefits, as well as providingadditional anti-bacterial benefits to mitigate the harmful effects ofbacteria as it relates to gum disease, including gingivitis,periodontitis, or both.

There is at least one of several drawbacks to the above describedconventional approaches. Firstly, these commercially available oral carecompositions may promote Gum Care, but they do not go far enough to alsopromote Gum Health. In fact, these commercially available oral carecompositions generally fail to provide any significant anti-bacterialeffects in addition to the Gum Care benefits (e.g., anti-bleeding and/oranti-swelling). This is a problem because if the bacteria in thebiofilms are not controlled, they can then increase the size of theperiodontal pockets leading to periodontitis. Secondly, Gum Health maycorrelate to overall body health. In other words, an individual's GumHealth can be an indicator of the person's overall body health. Studiessuggest that the risk of developing any one (or more) of these potentiallife-threatening conditions such as, for example, heart disease andstroke, diabetes, kidney disease, preterm birth, and/or osteoporosis,may increase as overall Gum Health decreases (see U.S. Pat. No.6,846,478; Doyle, M. J.; & U.S. Pat. No. 8,283,135; Doyle, M. J.). Thus,it is desirable to improve overall Gum Health, not just Gum Care, inorder to ensure better overall body health.

Stannous salts, such as stannous fluoride has been used in oral carecompositions as to provide Gum Health benefit, including antimicrobialeffect, reduced gingivitis, decreasing progression to periodontaldisease, reductions in dentinal hypersensitivity, and reduced coronaland root dental caries and erosion. However, there are disadvantages forconventional stannous containing compositions. A first side effectroutinely encountered during use of effective stannous fluorideformulations is unacceptable formulation astringency. Secondly,formulating stannous ions stably also presents a challenge as the tin(II) ion is both prone to oxidation towards tin (IV) and to precipitatefrom aqueous solution as stannous hydroxide. Therefore, it is desired tosimplify formulations and processing steps to provide cost effective andefficacious toothpaste and other oral care formulations.

Arginine has been reported for use in oral care and is believed to havesignificant benefits in combating cavity formation and toothsensitivity. However, commercially available arginine containing oralcare composition may have a basic pH, increasing potential for microbialcontamination compared to acidic formulation. Furthermore, anotherdisadvantage for arginine containing oral care compositions having basicpH is to discolor the compositions, turning them yellow to brown,especially when combined with stannous source. Thus, there is acontinuous need to provide an oral care composition having improvedstability over aging, without compromising the anti-microbial benefit.

Therefore, there is a continuous need to provide an oral carecomposition that provides Gum Health benefits to users, or at leastprovide better associated Gum Health benefits (e.g., gingival woundhealing and anti-bacterial benefits) than those compositions that arecommercially available.

SUMMARY OF THE INVENTION

The present invention attempts to address this need based, at least inpart, on the surprising discovery that the combination of citrulline anda stannous ion source, especially at a relatively low pH (e.g. pH <7.2)in an oral care composition promotes Gum Health benefits that include atleast gingival wound healing and anti-bacterial benefits, as well ashaving improved stability over aging. In particular, the oral carecomposition comprises citrulline for gingival wound healing, andstannous ion source as an anti-bacterial agent to combat the undesirableeffects of bacteria activity in the oral cavity.

One advantage of the present invention is “better deep biofilmpenetration and/or bacteria kill”. To this end, it is furthersurprisingly found that the penetration depth and/or penetration rate ofstannous ion into the biofilms may be increased, when used incombination with citrulline. In short, the synergistic combination ofcitrulline and stannous ion source at specific pH in the oral carecomposition may be such that an improvement in the Gum Health benefit isachieved. Furthermore, the use of the oral care compositions of thepresent invention may provide the users an improved Gum Health benefit.

Another advantage of the present invention is to provide oral carecompositions for promoting Gum Health as it relates to the totality ofsymptoms associated with gingivitis, periodontitis, or both. It is yet afurther advantage that the oral care compositions of the presentinvention have improved Gum Health benefits. It is yet a furtheradvantage of the present invention to provide oral care compositionshaving improved penetration depth of the anti-bacterial agent(s) intothe biofilms. It is yet a further advantage of the present invention toprovide oral care compositions having improved penetration rate of theanti-bacterial agent(s) into the biofilms. It is yet a further advantageof the present invention to provide cost effective and efficacious oralcare compositions for promoting Gum Health. It is yet a furtheradvantage that the oral care compositions have a stable quality of endproduct (e.g., consistent visual appearance and no discoloration,gingival wound healing performance, etc.) even after three monthsstorage at 40° C. It is yet a further advantage that the oral carecomposition, is a dentifrice, and preferably provides pleasant taste andmouth-feel experience. It is yet a further advantage that the oral carecompositions have physical and chemical stability across a range ofmanufacturing, handling and storage conditions. It is yet a stillfurther advantage that the oral care compositions of the presentinvention minimize the use of anti-bacterial agents. It is yet a stillfurther advantage that the oral compositions of the present inventionminimize the amount of the citrulline to reduce and/or eliminate theinstability and/or discoloration problems as described above. In oneaspect, the present invention is directed to an oral care compositioncomprising a stannous ion source and citrulline, wherein the oralcomposition has a pH of 7.2 or less. Preferably, the oral carecomposition comprising: a) from 0.01% to 5%, preferably from 0.05% to4%, by weight of the composition, of a stannous ion source; and b) from0.01% to 10%, preferably 0.05% to 5%, by weight of the composition, ofcitrulline, in free or salts form. Preferably, the oral care compositionhas a pH of from 5.0 to 7.0, more preferably from 5.5 to less than 7.0.

In another aspect of the present invention, the above mentioned oralcare composition further comprises c) from 0.05% to 1.5%, preferablyfrom 0.1% to 1%, and more preferably from 0.2% to 0.55% of a zinc ionsource, by weight of the composition. Preferably, the zinc ion source isselected from the group consisting of zinc citrate, zinc chloride, zincsulfate, zinc gluconate, zinc lactate, zinc phosphate, and combinationsthereof.

In yet another aspect of the present invention, a method is provided forpromoting Gum Health in a subject comprising administering to thesubject's oral cavity an oral care composition of the present invention.

In yet still another aspect of the present invention, there is provideda use of citrulline for making an oral care composition for promotingGum Health in a subject.

These and other features of the present invention will become apparentto one skilled in the art upon review of the following detaileddescription when taken in conjunction with the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims that particularly pointout and distinctly claim the invention, it is believed the presentinvention will be better understood from the following description ofthe accompanying figures.

FIG. 1 is a perspective view of an oral splint with Hydroxyapatite(“HA’) disks attached thereto.

FIG. 2 is a perspective view of the HA disk having grooves therein.

FIG. 3 is a schematic of a cross sectional view of the groove withbiofilm therein.

DETAILED DESCRIPTION OF THE INVENTION Definitions

As used herein, the articles including “a” and “an” when used in aclaim, are understood to mean one or more of what is claimed ordescribed.

The terms “alleviate” and “alleviating” are used interchangeably andmeans minimizing, preventing, delaying, and/or treating at least onesymptom of gum disease to effect positive change (i.e., benefit) to theuser.

The term “biofilms” as used herein means a matrix-enclosed bacterialpopulation adherent to each other and/or to surfaces or interfaces inthe oral cavity.

The term “comprising” as used herein means that steps and ingredientsother than those specifically mentioned can be added. This termencompasses the terms “consisting of” and “consisting essentially of.”The compositions of the present invention can comprise, consist of, andconsist essentially of the essential elements and limitations of theinvention described herein, as well as any of the additional or optionalingredients, components, steps, or limitations described herein.

The term “dentifrice” as used herein means paste, gel, powder, tablets,or liquid formulations, unless otherwise specified, that are used toclean the surfaces of the oral cavity.

The term “Gum Care” as used herein refers to inherent or promotedbenefits of an oral care composition directed, principally, toalleviating one or more symptoms associated with an early stage of gumdisease (i.e., gingivitis). Such symptoms may include, for examplebleeding gums; and red, swollen, or tender gums.

The term “Gum Health” as used herein refers to inherent or promotedbenefits of an oral care composition to provide “Gum Care” benefits thatinclude at least improve gingival wound healing, as well as, providingadditional improve reduction of bacterial activity to mitigate theharmful effects of bacteria as it relates to gum disease, includinggingivitis, periodontitis or both.

The term “improve reduction of bacterial activity” as used herein meansreduce bacterial activity in the oral cavity as determined by the assaydescribed in Example B.

The term “improve gingival wound healing” as used herein means reducegum bleeding in the oral cavity as determined by the wound healing assaydescribed in Example C. The term “oral care composition” or “oral carecompositions” as used herein means a product that in the ordinary courseof usage is retained in the oral cavity for a time sufficient to contactsome or all of the dental surfaces and/or oral tissues for purposes oforal activity. In one example, the composition provides a gum carebenefit when used in the oral cavity. The oral care composition of thepresent invention may be in various forms including toothpaste,dentifrice, tooth gel, tooth powders, tablets, rinse, mouthwash, subgingival gel, foam, mouse, chewing gum, lipstick, sponge, floss, prophypaste, petrolatum gel, denture adhesive, or denture product. In oneexample, the oral composition is in the form of a paste or gel. Inanother example, the oral composition is in the form of a dentifrice.The oral composition may also be incorporated onto strips or films fordirect application or attachment to oral surfaces, or incorporated intofloss.

The term “amino acid” used herein the present invention refers to theamino acid including both in free form and salts form.

The term “partially water soluble” as used herein means a compound has asolubility of 1 g/1000 ml or more at 25° C.

The term “effective amount” as used herein means an amount of a compoundor composition sufficient to induce a positive benefit, an oral healthbenefit, and/or an amount low enough to avoid serious side effects,i.e., to provide a reasonable benefit to risk ratio, within the soundjudgment of a skilled artisan. In one example, “effective amount” meansat least 0.01% of the material, by weight of the composition,alternatively at least 0.1%.

As used herein, the words “preferred”, “preferably” and variants referto embodiments of the invention that afford certain benefits, undercertain circumstances. However, other embodiments may also be preferred,under the same or other circumstances. Furthermore, the recitation ofone or more preferred embodiments does not imply that other embodimentsare not useful, and is not intended to exclude other embodiments fromthe scope of the invention.

The term “promoting” as used herein means to promote and/or enhance theGum Health benefits associated with using the oral care compositions ofthe present invention in the oral cavity.

The term “substantially free” as used herein refers to no intentionalamount of that material is added to the composition or an amount of amaterial that is less than 0.05%, 0.01%, or 0.001% of the composition.The term “essentially free” as used herein means that the indicatedmaterial is not deliberately added to the composition, or preferably notpresent at analytically detectable levels. It is meant to includecompositions whereby the indicated material is present only as animpurity of one of the other materials deliberately added. The term“free” as used herein refers to no reasonably detectable amount of thatmaterial is present in the composition.

The term “synergistic Gum Health benefit” as used herein meansanalytically measurable increases in any two Gum Health benefits thatinclude at least improve gingival wound healing and improve reduction ofbacterial activity in the oral cavity, that is more than additive.

The term “teeth” as used herein refers to natural teeth as well asartificial teeth or dental prosthesis.

The term “total water content” as used herein means both free water andwater that is bound by other ingredients in the oral care composition.

All percentages, parts and ratios are based upon the total weight of thecompositions of the present invention, unless otherwise specified. Allsuch weights as they pertain to listed ingredients are based on theactive level and, therefore do not include solvents or by-products thatmay be included in commercially available materials, unless otherwisespecified.

All measurements referred to herein are made at 25° C. (i.e., roomtemperature) unless otherwise specified.

Oral Care Compositions

It has been surprisingly discovered that the combination of stannous ion(i.e., an anti-bacterial agent) and citrulline, especially at pH of 7.2or less, in an oral care composition is particularly useful forpromoting Gum Health benefits to users. In particular, the surprisingdiscovery was that the penetration of the stannous ion into the biofilmsis markedly improved when combined with citrulline. Without wishing tobe bound by theory, the citrulline contains both carboxylic and aminogroups. It is believed that the stannous ions can bind strongly to thesechemical moieties on amino acid to positively influence the penetrationof stannous ions into the biofilms.

It has also been surprisingly found that the penetration depth and/orthe penetration rate of stannous ions into the biofilms may beincreased, or markedly increased, when formulated with citrulline. Inshort, the presence of citrulline in combination with stannous ionsource in an oral care composition aids the composition's efficacy inmediating the harmful effects of the bacteria in the biofilms on thegums.

In one aspect, the present invention is directed to an oral carecomposition comprising: a) from 0.01% to 5%, preferably from 0.05% to4%, more preferably from 0.1% to 2%, by weight of the composition, of astannous ion source; b) from 0.01% to 10%, preferably from 0.05% to 8%,more preferably from 0.1% to 5%, by weight of the composition, ofcitrulline, wherein the oral care composition has a pH of 7.2 or less.

pH

The oral care compositions of the present invention have a pH of 7.2 orless, preferably from 5.0 to 7.2. Preferably, the pH is less than 7.2,more preferably the pH is 7.0 or less, even more preferably the pH isfrom pH 5.0 to 7.0, alternatively the pH is from pH 5.5 to less than7.0, e.g., pH 6.9, or pH 6.8, or pH 6.7, or pH 6.6, or pH 6.5, or pH6.4, or pH 6.3, or pH 6.2, or pH 6.2, or pH 6.1, or pH 6.0, or pH 5.9,or pH 5.8, or pH 5.7, or pH 5.6, or pH 5.5. The relatively low pH of thepresent inventive composition is for alleviating discoloration andoptionally avoiding the precipitation of stannous. Without wishing to bebound theory, at above pH 7.3 stannous ion may increase the possibilityof discoloration. Thus, it is desirable to have the oral carecomposition with a pH less than 7.2 to alleviate discoloration.

Citrulline

Citrulline used in the present invention may be present in the amount offrom 0.01% to 15%, preferably from 0.05% to 10%, for example 0.5%, or1%, or 1.5%, or 2%, or 3%, or 4%, or 5%, or 6%, or 7%, or 8%, by weightof the composition. Alternatively, citrulline is present in the amountof from 0.1% to 8%, or from 0.5% to 5%, or from 0.2 to 3%, by weight ofthe composition. Citrulline used herein may be in free form or in saltform. If in salt form, suitable salts include salts known in the art tobe pharmaceutically acceptable salts considered to be physiologicallyacceptable in the amounts and concentrations provided. For example,L-citrulline malate, L-citrulline DL-malate, L-citrulline ethylestermonohydrochloride can be suitable salts form of citrulline.

It has been surprisingly discovered that, keeping the oral carecomposition at a relatively low pH range (7.2 or less) provides the endoral care product a stable quality (e.g., consistent visual appearanceand less discoloration), compared with at a higher pH (7.3 or more).Without wishing to be bound by theory, pH has a significant effect onthe Maillard reaction which cause the undesirable browning/discolorationof an oral care composition over time. Specifically, the rate and extentof browning increases with increasing pH. Therefore, lowering pHalleviate the browning reaction and achieve better user desirableappearance.

Furthermore, the introductions of amino acid provide gingival wouldhealing benefit and thus be able to minimize the use of otheranti-bleeding agents, for example tranexamic acid, epsilon aminocaproicacid, and p-aminomethylbenzoic acid. In some preferred examples, theoral care composition of the present invention is substantially free of,preferably essentially free of, and more preferably free of, tranexamicacid, epsilon aminocaproic acid, and p-aminomethylbenzoic acid.

Stannous Ion Source

The present invention relates to the above mentioned oral carecompositions comprising, in a preferred example, the stannous ion sourcepresent in the amount of from 0.01% to 5%, preferably from 0.05% to 4%,or more preferably from 0.1% to 2%, by weight of the composition, toprovide anti-bacterial effectiveness. The stannous ion source usedherein may include any safe and effective stannous salt. Suitableexamples of stannous ion source are selected from the group consistingof stannous chloride, stannous fluoride, stannous acetate, stannousgluconate, stannous oxalate, stannous sulfate, stannous lactate,stannous tartrate, stannous iodide, stannous chlorofluoride, stannoushexafluorozirconate, stannous citrate, stannous malate, stannousglycinate, stannous carbonate, stannous phosphate, stannouspyrophosphate, stannous metaphosphate, and combinations thereof.Preferably, the stannous ion source is selected from stannous fluoride,stannous chloride, and combinations thereof. In one preferred example,the stannous ion source comprises stannous chloride. In anotherpreferred example, the stannous ion source comprises stannous fluoride.

Zinc Ion Source

Optionally, but preferably, the oral care composition may furthercomprise from 0.1% to 5%, preferably from 0.2% to 2%, by weight of thecomposition, of a zinc ion source. Preferably, the zinc ion source isselected from the group consisting of zinc citrate, zinc chloride, zincsulfate, zinc gluconate, zinc lactate, zinc phosphate, and combinationsthereof. More preferably, the zinc ion source is selected from zinccitrate, zinc gluconate, zinc lactate, and combinations thereof.

Insoluble or sparingly soluble zinc compounds, such as zinc oxide orzinc carbonate, can be used as the zinc source. Preferred zinc sourceshowever are soluble zinc sources such as zinc chloride or zinc sulfate.More preferred zinc sources are those where the zinc is already combinedwith a suitable chelating agent in the form of a salt or other complex,such as zinc citrate, zinc gluconate, zinc lactate and zinc glycinate.Especially preferred sources of zinc ions are zinc citrate, zincgluconate, zinc lactate and mixtures thereof. Preferably, the oral carecomposition may comprise a soluble source of zinc ions from 0.1% to1.5%, preferably from 0.15% to 1%, or more preferably from 0.2% to 0.55%by weight of the composition.

When insoluble and soluble zinc compounds are both present in the zincion source, preferably the soluble zinc compound is present at least50%, by weight of the total zinc ion source.

The oral care compositions of the present invention may optionally alsoinclude other anti-bacterial agents, preferably present in an amount offrom 0.035% or more, from 0.05% to 2%, from 0.1% to 1%, by weight of thecomposition. Examples of these other anti-bacterial agents may includenon-cationic anti-bacterial agents such as, for example, halogenateddiphenyl ethers, phenolic compounds including phenol and its homologs,mono and poly-alkyl and aromatic halophenols, resorcinol and itsderivatives, xylitol, bisphenolic compounds and halogenatedsalicylanilides, benzoic esters, and halogenated carbanilidies. Otheruseful anti-bacterial agents are enzymes, including endoglycosidase,papain, dextranase, mutanase, and combinations thereof. In anotherexample, the other anti-bacterial agent can include triclosan(5-chloro-2-(2,4-dichlorophenoxy)phenol).

Thickening Agent

The oral care compositions of the present invention may comprise athickening agent.

Preferably the oral care composition comprises from 0.1% to 5%,preferably from 0.8% to 3.5%, more preferably from 1% to 3%, yet stillmore preferably from 1.3% to 2.6%, by weight of the composition, of thethickening agent.

Preferably, the thickening agent comprises a thickening polymer, athickening silica, or a combination thereof. Yet more preferably, whenthe thickening agent comprises a thickening polymer, the thickeningpolymer is selected from a charged carboxymethyl cellulose, a non-ioniccellulose derivative, a linear sulfated polysaccharide, a natural gum,polymers comprising at least a polycarboxylated ethylene backbone, andcombinations thereof.

In one example, the thickening silica is obtained from sodium silicatesolution by destabilizing with acid as to yield very fine particles. Onecommercially available example is ZEODENT® branded silicas from HuberEngineered Materials (e.g., ZEODENT® 103, 124, 113 115, 163, 165, 167).

Preferably, the linear sulfated polysaccharide is a carrageenan (alsoknown as carrageenin). Examples of carrageenan includeKappa-carrageenan, Iota-carrageenan, Lambda-carrageenan, andcombinations thereof.

In one example, the CMC is prepared from cellulose by treatment withalkali and monochloro-acetic acid or its sodium salt. Differentvarieties are commercially characterized by viscosity. One commerciallyavailable example is Aqualon™ branded CMC from Ashland SpecialIngredients (e.g., Aqualon™ 7H3SF; Aqualon™ 9M3SF Aqualon™ TM9A;Aqualon™ TM12A).

Preferably, a natural gum is selected from the group consisting of gumkaraya, gum arabic (also known as acacia gum), gum tragacanth, xanthangum, and combination thereof. More preferably the natural gum is xanthangum. Xanthan gum is a polysaccharide secreted by the bacteriumXanthomonas camestris. Generally, xanthan gum is composed of apentasaccharide repeat units, comprising glucose, mannose, andglucuronic acid in a molar ratio of 2:2:1, respectively. The chemicalformula (of the monomer) is C₃₅H₄₉O₂₉. In one example, the xanthan gumis from CP Kelco Inc (Okmulgee, US).

Preferably, the non-ionic cellulose or derivative thereof has an averagemolecular weight range of 50,000 to 1,300,000 Daltons, and preferably anaverage degree of polymerization from 300 to 4,800. More preferably, thenon-ionic cellulose or derivative thereof is hydroxyethyl cellulose(“HEC”).

Preferably, the polymer comprising at least a polycarboxylated ethylenebackbone is selected from the group consisting of: co-polymers of maleicanhydride with methyl vinyl ether having a molecular weight of 30,000 to1,000,000 Daltons; homo-polymers of acrylic acid; and co-polymers ofmaleic acid and acrylic acid or methacrylic.

The co-polymers of maleic anhydride with methyl vinyl ether are at leastone of: Gantrez AN139 (M.W. 500,000 daltons), Gantrez AN119 (M.W.250,000 daltons), or S-97 Pharmaceutical Grade (M.W. 70,000 daltons);and the homo-polymers of acrylic acid and co-polymers of maleic acid andacrylic acid or methacrylic acid are at least one of: Acusol 445, Acusol445N, Accusol 531, Acusol 463, Acusol 448, Acusol 460, Acusol 465,Acusol 490, Sokalan CPS, Sokalan CP7, Sokalan CP45, or Sokalan CP12S;and (v) combinations thereof.

In an example, the GANTREZ™ series of polymers are co-polymers of maleicanhydride with methyl vinyl ether having a molecular weight (M.W.) of30,000 daltons to 1,000,000 daltons. These co-polymers are available forexample as GANTREZ™ AN139 (M.W. 500,000 daltons), AN119 (M.W. 250,000daltons) and S-97 Pharmaceutical Grade (M.W. 70,000 daltons), fromAshland Chemicals (Kentucky, USA).

In another example, the ACUSOL™ and the SOKALAN series of polymersinclude homopolymers of acrylic acid and copolymers of maleic acid andacrylic acid or methacrylic. Examples are 0:1000 to 1000:0 copolymers ofmaleic acid with acrylic acid having a molecular weight (M.W.) of about2,000 to about 1,000,000. These copolymers are commercially available asACUSOL™ 445 and 445N, ACUSOL™ 531, ACUSOL™ 463, ACUSOL™ 448, ACUSOL™460, ACUSOL™ 465, ACUSOL™ 497, ACUSOL™ 490 from Dow Chemicals (Michigan,USA) and as Sokalan® CP 5, Sokalan® CP 7, Sokalan® CP 45, and Sokalan®CP 12 S from BASF (New Jersey, USA).

In another example, the crosslinked polyacrylic acid (PAA) polymer is ageneric term for the synthetic high molecular weight polymers of acrylicacid. These may be homopolymers of acrylic acid, crosslinked with anallyl ether pentaerythritol, allyl ether of sucrose or allyl ether ofpropylene. And, in a water solution at neutral pH, PAA is an anionicpolymer, i e many of the side chains of PAA will lose their protons andacquire a negative charge. Carbopol®-type polymers, such as Carbopol®,Pemulen® and Noveon®, are polymers of acrylic acid, crosslinked withpolyalkenyl ethers or divinyl glycol. Carbomer commercial codes, e.g.940™, indicate the molecular weight and the specific components of thepolymer.

Anti-Caries Agent

Optionally, but preferably, the oral care compositions may include aneffective amount of an anti-caries agent. In one aspect, the anti-cariesagent is a fluoride ion source. Suitable examples of fluoride ions maybe selected from a source comprising stannous fluoride, sodium fluoride,potassium fluoride, sodium monofluorophosphate (“MFP”), indium fluoride,amine fluoride, zinc fluoride, and mixtures thereof. Preferably, thefluoride ion source is selected from sodium fluoride, stannous fluoride,MFP, or combinations thereof. The fluoride ion source may be present inan amount of from 0.0025% to 10%, or from 0.05% to 4%, or from 0.1% to2%, or preferably from 0.2% to 1.5%, by weight of the composition, toprovide anti-caries effectiveness. In certain examples, the fluoride ionsource can be present in an amount sufficient to provide fluoride ionsconcentration in the composition at levels from 25 ppm to 25,000 ppm,generally at least from 500 ppm to 1600 ppm, for example 1100 ppm or1450 ppm. The appropriate level of fluoride will depend on theparticular application. A toothpaste for general user would typicallyhave about 1000 to 1500 ppm, with pediatric toothpaste having somewhatless.

pH Measurement

The pH is typically measured using a ratio of 1:3 of paste:water,whereby 1 gram of the oral care composition (e.g., toothpaste) is mixedinto 3 grams of deionized water, and then the pH is assessed with anindustry accepted pH probe that is calibrated under ambient conditions.The pH is measured by a pH meter with Automatic Temperature Compensating(ATC) probe. For purposes of clarification, although the analyticalmethod describes testing the oral care composition when freshlyprepared, for purposes of claiming the present invention, the pH may betaken at any time during the product's reasonable lifecycle (includingbut not limited to the time the product is purchased from a store andbrought to the user's home).

After each usage the electrode should be washed free from the samplesolution with water. Remove any excess water by wiping with a tissue,such as Kimwipes or equivalent. When electrode is not in use, keepelectrode tip immersed in pH 7 buffer solution or electrode storagesolution. Equipment details are as follows:

-   -   pH Meter: Meter capable of reading to 0.01 or 0.001 pH units.    -   Electrode: Orion Ross Sure-Flow combination: Glass body—VWR        #34104-834/Orion #8172BN or VWR#10010-772/Orion #8172BNWP. Epoxy        body—VWR #34104-830/Orion #8165BN or VWR#10010-770/Orion        #8165BNWP. Semi-micro, epoxy body—VWR #34104-837/Orion #8175BN        or VWR#10010-774/Orion #3175BNWP. Orion PerpHect combination:        VWR #34104-843/Orion #8203BN semi-micro, glass body.    -   ATC Probe: Fisher Scientific, Cat. #13-620-16.

pH Modifying Agent

The oral care compositions herein may optionally include an effectiveamount of a pH modifying agent, alternatively wherein the pH modifyingagent is a pH buffering agent. The pH modifying agents, as used herein,refer to agents that can be used to adjust the pH of the oral carecompositions to the above-identified pH range. The pH modifying agentsinclude hydrochloric acid, alkali metal hydroxides, ammonium hydroxide,organic ammonium compounds, carbonates, sesquicarbonates, borates,silicates, phosphates, imidazole, and mixtures thereof.

Specific pH modifying agents include monosodium phosphate (monobasicsodium phosphate), trisodium phosphate (sodium phosphate tribasicdodecahydrate or TSP), sodium benzoate, benzoic acid, sodium hydroxide,potassium hydroxide, alkali metal carbonate salts, sodium carbonate,imidazole, pyrophosphate salts, linear or cyclic polyphosphates salts,sodium gluconate, lactic acid, sodium lactate, citric acid, sodiumcitrate, phosphoric acid.

In one example, 0.01% to 3%, preferably from 0.1% to 1% of TSP by weightof the composition, and 0.001% to 2%, preferably from 0.01% to 0.3% ofmonosodium phosphate by weight of the composition is used. Withoutwishing to be bound by theory, TSP and monosodium phosphate may havecalcium ion chelating activity and therefore provide somemonofluorophosphate stabilization (in those formulations containingmonoflurophospahte).

Water

Water is commonly used as a carrier material in oral care compositionsdue to its many benefits. For example, water is useful as a processingaid, is benign to the oral cavity and assists in quick foaming oftoothpastes. Water may be added as an ingredient in its own right or itmay be present as a carrier in other common raw materials such as, forexample, sorbitol and sodium lauryl sulfate.

In some examples, the oral care compositions herein may include from 10%to 70%, or preferably from 15% to 30%, by weight of the composition, oftotal water content. The term “total water content” as used herein meansthe total amount of water present in the oral care composition, whetheradded separately or as a solvent or carrier for other raw materials butexcluding that which may be present as water of crystallization incertain inorganic salts. Preferably, the water is USP water.

Alternatively, in other examples, the oral care compositions herein mayinclude from 0% to 5%, by weight of the composition, of total watercontent. For example, the oral care composition may be substantiallyfree of water, preferably free of water.

Surfactant

Optionally, but preferably, the oral care compositions comprise asurfactant. The surfactant may be selected from anionic, nonionic,amphoteric, zwitterionic, cationic surfactants, or combinations thereof,preferably the surfactant is anionic, more preferably the anionicsurfactant is sodium lauryl sulfate (SLS). An example of a zwitterionicsurfactant is cocamidopropyl betaine. The oral care composition maycontain one, two, or more surfactants. The composition may include asurfactant at a level of from 0.1% to 20%, preferably from 1% to 10%, byweight of the total composition.

Humectants

The oral care compositions herein may include humectants present in theamount of from 0% to 70%, or from 15% to 55%, by weight of thecompositions. Humectants keep oral care compositions from hardening uponexposure to air and certain humectants may also impart desirablesweetness of flavor to oral care compositions. Suitable examples ofhumectants may include glycerin, sorbitol, polyethylene glycol,propylene glycol, xylitol, trimethyl glycine, and mixtures thereof.Other examples may include other edible polyhydric alcohols. In someexamples, the humectant is selected from sorbitol, glycerin, andcombinations thereof. Preferably the humectant is sorbitol. In anexample, the composition comprises from 10% to 66%, alternatively from30% to 55%, of humectant by weight of the composition.

Abrasives

The oral care composition comprises an effective amount of an abrasive.Examples of abrasives include a calcium-containing abrasive, a silica,or combinations thereof. If containing a calcium-containing abrasive,the calcium-containing abrasive is preferably selected from the groupconsisting of calcium carbonate, dicalcium phosphate, tricalciumphosphate, calcium orthophosphate, calcium metaphosphate, calciumpolyphosphate, calcium oxyapatite, sodium carbonate, sodium bicarbonate,and combinations thereof. If a silica, preferably the silica is aprecipitated silica (e.g., sodium silicate solution by destabilizingwith acid as to yield very fine particles) such as those from theZEODENT® series from Huber Engineered Materials (e.g., ZEODENT® 103,124, 113 115, 163, 165, 167). It is acknowledged that some of thesesilicas (e.g., synthetic amorphous silica) can perform both abrasive andthickening functions, but are included herein under the term “abrasive”for purposes of the present invention. Preferably the oral carecomposition comprises from 1% to 35%, more preferably from 5% to 25% ofabrasive, by weight of the composition.

Flavoring Agent

The oral care composition herein may include from 0.01% to 5%,preferably from 0.1% to 2%, by weight of the composition, of a flavoringagent. Examples of suitable flavoring agent that may be used in the oralcare composition include those described in U.S. Pat. No. 8,691,190;Haught, J. C., from column 7, line 61 to column 8, line 21. In someexamples, the flavoring agent may be selected from methyl salicylcate,menthol, eugenol and cineol. In some examples, the oral care compositionmay comprise a flavor mixture which is free of or substantially free ofmethyl salicylcate, menthol, eugenol and cineol.

Sweetener

The oral care compositions herein may include a sweetening agent. Thesweetening agent is generally present in the oral care compositions atlevels of from 0.005% to 5%, by weight of the composition. Suitableexamples of sweetener include saccharin, dextrose, sucrose, lactose,xylitol, maltose, levulose, aspartame, sodium cyclamate, D-tryptophan,dihydrochalcones, acesulfame, sucralose, neotame, and mixtures thereof.Other suitable examples of sweetener are described in U.S. Pat. No.8,691,190; Haught, J. C. from column 9, line 18 to column 10, line 18.

Coloring Agents

The oral care compositions herein may include a coloring agent presentin the amount of from 0.001% to 0.01%, by weight of the compositions.The coloring agent may be in the form of an aqueous solution, preferably1% coloring agent in a solution of water. Suitable examples of coloringagents may include pigments, pealing agents, filler powders, talc, mica,magnesium carbonate, calcium carbonate, bismuth oxychloride, zinc oxide,and other materials capable of creating a visual change to the oral carecompositions. Other suitable examples may include titanium dioxide(TiO₂). Titanium dioxide is a white powder which adds opacity to thecompositions and is generally present in the oral care compositions atlevels of from 0.25% to 5%, by weight of the composition.

Other Ingredients

The present oral care composition can comprise the usual andconventional ancillary components that are known to one skilled in theart. Optional ingredients include, for example, but are not limited to,anti-plaque agent, anti-sensitivity agent, whitening and oxidizingagent, anti-inflammatory agent, anti-calculus agent, chelating agent,tooth substantive agent, analgesic and anesthetic agent. It will beappreciated that selected components for the oral care compositions mustbe chemically and physically compatible with one another.

Method of Use

In one aspect, the present invention relates to a method for cleaning orpolishing teeth in a subject. The method of cleaning or polishing hereincomprises contacting a subject's teeth with the oral care compositionsaccording to the present invention.

In another aspect, the present invention also relates to a method ofpromoting Gum Health in a subject comprising administering to thesubject's oral cavity an oral care composition according to the presentinvention, wherein preferably the administering occurs at least once aday, more preferably at least twice a day.

In yet another aspect, the present invention relates to a use ofcitrulline for making an oral care composition for promoting Gum Healthin a subject. Preferably, the method of promoting Gum Health occurs atleast within a period selected from the group consisting of:

a) from time 0 hours to 72 hours;

b) from time 0 hours to 48 hours;

c) from time 0 hours to 24 hours;

-   -   wherein time 0 hour is the time when the oral care composition        according to the present invention is administrated.

In yet another aspect, the present invention also relates to a method ofpromoting Gum Health, wherein promoting Gum Health comprising:

(i) improving gingival wound healing in the oral cavity; and

(ii) improve reduction of bacterial activity in the oral cavity.

The methods as described above may be by brushing (e.g., toothbrushing)with an oral care composition (e.g., dentifrice) or rinsing with an oralcare composition (e.g., dentifrice slurry or mouth rinse). The oral carecompositions may be applied neat or via a delivery apparatus such as,for example, a toothbrush. Other methods include contacting the topicaloral gel, mouth spray, toothpaste, dentifrice, tooth gel, tooth powders,tablets, subgingival gel, foam, mouse, chewing gum, lipstick, sponge,floss, petrolatum gel, or denture product or other form with thesubject's teeth and oral mucosa. Depending on the embodiment, the oralcare composition may be used as frequently as toothpaste, or may be usedless often, for example, weekly, or used by a professional in the formof a prophy paste or other intensive treatment.

EXAMPLES

The following examples and descriptions further clarify embodimentswithin the scope of the present invention. These examples are givensolely for the purpose of illustration and are not to be construed aslimitations of the present invention as many variations thereof arepossible without departing from the spirit and scope.

Example A: Examples 1 to 11

Examples 1 to 11 are dentifrice compositions shown below with amounts ofcomponents in wt %. They may be suitably prepared by conventionalmethods chosen by the formulator. Examples 1-6 are inventiveformulations according to the present invention, made with a stannousion source and citrulline at different concentrations at a specific pH.Example 7 is made with a stannous and citrulline with a relative highmount of zinc. Example 8 is made without citrulline.

Example 9 is made without the stannous ion source. Example 10 is madewith stannous and citrulline, but having a pH outside the scope of thepresent invention. Example 11 is a comparative example without stannousnor citrulline nor zinc. All of the compositions are prepared byadmixture of the components in Tables 1 and 2, in the proportionsindicated.

TABLE 1 Examples 1 to 6 Amount (Wt %) Ingredients Ex. 1 Ex. 2 Ex. 3 Ex.4 Ex. 5 Ex. 6 Sorbitol Solution 70% 48.000  48.000  48.000  48.000 48.000  — (Archer Daniels Midland) Sodium Fluoride 0.321 0.321 0.3210.321 0.321 — Citrulline 0.50  2.00  2.00  2.00  8.00  2.00 Glycerin — —— — — 35.500 Propylene Glycol — — — — — 7.000 PEG-6 — — — — — 7.000Sodium Polyphosphate — — — — — 13.000 Trosodium Phosphate — — — — —1.100 Dodecahydrate Stannous Fluoride — — — — — 0.454 Zinc LactateDihydrate — — — — — 1.900 Zinc Citrate 0.533 — 0.533 0.533 0.533 —Stannous Chloride 1.160 1.160 1.160 1.160 1.160 0.462 Dihydrate SodiumGluconate 1.064 1.064 1.064 1.064 1.064 1.099 Xanthan Gum 0.875 0.8750.875 0.875 0.875 0.250 Carrageenan Mixture 1.500 1.500 1.500 1.5001.500 0.600 Iota Silica Silica Abrasive 16.000  16.000  16.000  16.000 16.000  25.000 Thickening Silica — — — — — 0.750 Sodium Lauryl Sulfate5.000 7.500 5.000 5.000 7.500 3.400 (28% soln.) Sodium Saccharin 0.3000.250 0.300 0.300 0.250 0.700 Flavor/sensate oils 1.100 1.100 1.1001.100 1.100 1.200 Sodium Hydroxide 0.980 0.980 0.980 0.980 0.980 — Waterand minors (e.g., q.s. q.s. q.s. q.s. q.s. qs color soln.) Total 100%100% 100% 100% 100% 100% Target pH 6.5  6.5  6.5  7.0  6.5  5.7

TABLE 2 Examples 7 to 11 Amount (Wt %) Ingredients Ex. 7 Ex. 8 Ex. 9 Ex.10 Ex. 11 Sorbitol Solution 70% 48.000 48.000 48.000 48.000 48.000Sodium Fluoride 0.321 0.321 0.321 0.321 0.321 Citrulline 2.00 — 2.002.00 — Zinc Citrate 1.066 0.533 — 0.533 — Stannous Chloride Dihydrate1.160 1.160 — 1.160 — Sodium Gluconate 1.064 1.064 1.064 1.064 1.064Xanthan Gum 0.875 0.875 0.875 0.875 0.875 Carrageenan Mixture Iota 1.5001.500 1.500 1.500 1.500 Silica Silica Abrasive 16.000 16.000 16.00016.000 16.000 Sodium Lauryl Sulfate 5.000 5.000 5.000 5.000 5.000 (28%soln.) Sodium Saccharin 0.300 0.300 0.300 0.300 0.300 Flavor 1.100 1.1001.100 1.100 1.100 Sodium Hydroxide 0.980 0.980 0.980 0.980 0.980 Waterand minors q.s. q.s. q.s. q.s. q.s. (e.g., color soln.) Total 100% 100%100% 100% 100% Target pH 6.5 6.5 6.5 7.3 6.5

Example B.—Assay for Measuring Improve Penetration of Anti-BacterialAgent in the Biofilms

In order to determine improved penetration of anti-bacterial agent inthe biofilms, the following assay is used to assess penetrationefficiency of stannous ions with bacteria via measurement ofco-localization percentage in in situ plaque biofilms for inventive oralcare compositions of the present invention and controls. Details of theassay are described below.

(a) Substrate for Biofilm Growth

Hydroxyapatite (“HA”) disks are used for in situ growth of biofilms. TheHA disks are designed having three parallel grooves (i.e., 200 um wide;200 μm deep for two sides' grooves; while 500 μm wide and 500 μm deepfor the middle groove) in each disk. When attaching disks to subject'smouth, keep these grooves vertical, to mimic interproximal gap betweenteeth, which is the hard-to-clean area where plaque generally tends toaccumulate. This model allows the collection of undisturbed plaque fromthe grooves. HA disks are manufactured by Shanghai Bei'erkangbiomedicine limited company (Shanghai, China).

(b) Wearing the Splint

Human subjects wear the splint. Each subject wears up to 12 HA disks onthe splint to ensure that, at least, 9 HA disks are available after 48hours. A non-limiting example of such a splint and HA disks are shown inFIG. 1. With reference to FIG. 1, the device (1) holds a plurality of HAdisks (2 a-2 d). In a specific example, and with reference to FIG. 2,the HA disk (201) has three parallel grooves (203) (the two sides'grooves (203 a and 203c) are 300 μm wide and 300 μm deep; while themiddle grove (203 b) (in between the two side grooves) is 500 um wideand 500 μm deep). The middle groove is designed wider and deeper thanthe two sides' grooves so that the HA disk can be more easily separatedinto two identical half-disks for head-to-head comparison purposes. FIG.3 is a schematic of a cross-sectional view of the groove (2003) withbiofilm (2005) therein. Further details of the HA disks are described inPCT patent application no. PCT/CN2015/089238, with the internationalfiling date of Sep. 9, 2015.

Although not shown in FIG. 3, the disks can be positioned such that therecede is in the inter-dental space between the teeth (since thislocation is prone to plaque (given the difficulty in cleaning, etc.)).The subjects withdraw the splint only during meals (the splint stored inan opaque container in humid conditions) and to perform oral hygieneprocedures Immediately thereafter, the splint is worn again. Subjectsare asked to use a straw when drinking.

(c) In-situ Biofilms Release from HA Desk

All HA disks are removed from the splint at 48 hours by tweezers.Tweezers are used to hold the edge of HA chips and transfer the HA diskto a 2 mL centrifuge tube containing phosphate buffered saline (PBS)solution. Tweezers are washed thoroughly (water; 75% alcohol; and thendeionized water) before every disk transfer.

(d) Preparation of Toothpaste Supernatant

15 grams of deionized water is added to 5 grams toothpaste (using anyone of the Examples 1-11). After stirring thoroughly, the mixture iscentrifuge at 12,000 RPM for 20 minutes. The supernatant is prepared oneday before usage and stored at 4° C.

(e) Confocal Laser Scanning Microscopy

After the HA disks are removed from the splint. The HA disks are usedfor ex vivo treatment by the different inventive and Comparativecompositions. After being treated with the subject supernatant andlabeled with microbial fluorescent probe and stannous fluorescent probe(such as described in US2018/0072944A1; Shi et al.), the biofilms in thegrooves are measured by confocal laser scanning microscopy (“CLSM”) (asdescribed below). Preferably, the stannous fluorescent probe istert-butoxy-carboxamide,N-[3′,6′-bis(diethylamino)-3-oxospiro[1H-isoindole-1,9′-[9H]xanthen]-H)-yl](available from Dr. Tao Yi, Fudan University, Shanghai, China).Preferably, the microbial fluorescent probe is the Molecular Probes™LIVE/DEAD® BacLight™ system (available from Thermo Fisher).

(f) Disk Preparation

The HA disks are rinsed in PBS solution and each HA disk is divided intotwo halves by tweezers. Thereafter, each half-disk is placed into500-1000 μL of PBS solution statically for 1 minute. Each disk istreated for two minutes by either PBS solution or toothpastesupernatant. Each disk is washed by holding each disk with tweezers,shaken for ten rounds of back and forth in 1 mL of PBS solution, andthen this washing cycle is repeated. Then each disk is immersed into500-1000 μL PBS solution statically for 5 minutes.

(g) Fluorescence Staining and Microscopy

After treatment and immersing, each half-disk is stained with the Snprobe together with Syto-9 probe (containing 5 μM Syto-9 and 5 μM Snprobe) for 30 minutes in the dark. After staining, each disk is immersedinto 500-1000 μL PBS solution statically for 2 minutes. The disks arewashed again, by holding each disk with tweezers, shaken for five roundsof back and forth in 1 mL PBS solution, and repeated. For SYTO-9/Sn dyestained samples, the following parameters are used: λ_(ex)=488 nm/543nm, λ_(em)=500/580 nm, 20× objective lens, and scanning from bottom ofsurface bacteria for 60 μm with step size=3 um.

(h) Confocal Laser Scanning Microscopy

The Leica™ TCS SP8 AOBS spectral confocal microscope is used. Theconfocal system consists of a Leica™ DM6000B upright microscope and aLeica™ DMIRE2 inverted microscope. An upright stand is used forapplications involving slide-mounted specimens; whereas the invertedstand, having a 37° C. incubation chamber and CO₂ enrichmentaccessories, provides for live cell applications. The microscopes sharean exchangeable laser scan head and, in addition to their ownelectromotor-driven stages, a galvanometer-driven high precision Z-stagewhich facilitates rapid imaging in the focal (Z) plane. In addition toepifluorescence, the microscopes support a variety of transmitted lightcontrast methods including bright field, polarizing light anddifferential interference contrast, and are equipped with 5×, 20×, 40×,63× (oil and dry) and 100× (oil) Leica™ objective lenses.

The laser scanning and detection system is described. The TCS SP8 AOBSconfocal system is supplied with four lasers (one diode, one argon, andtwo helium neon lasers) thus allowing excitation of a broad range offluorochromes within the UV, visible and far red ranges of theelectromagnetic spectrum. The design of the laser scan head, whichincorporates acousto-optical tunable filters (“AOTF”), anacousto-optical beam splitter (“AOBS”) and four prism spectrophotometerdetectors, permits simultaneous excitation and detection of threefluorochromes. The upright microscope also has a transmission lightdetector making it possible to overlay a transmitted light image upon afluorescence recording.

Leica™ Confocal software is used. The confocal is controlled via astandard Pentium PC equipped with dual monitors and running Leica™Confocal Software. The Leica Confocal Software provides an interface formulti-dimensional image series acquisition, processing and analysis,that includes 3D reconstruction and measurement, physiological recordingand analysis, time-lapse, fluorochrome co-localization, photo-bleachingtechniques such as FRAP and FRET, spectral immixing and multicolourrestoration. Regarding image analysis, the SYTO-9/Sn dye stained samplesare chosen to quantify overlap efficiency of red and green pixels. Usingthe software, the pixel overlap of “green” bacterial probes and that of“red” stannous probes are identified, and then this value is divided byall non-black pixels (that include non-overlapping stannous probes) toprovide a co-localization percentage of stannous in bacteria. Generally,the higher this co-localization percentage, the more efficacious theoral care product is in delivering stannous into bacteria. (See Xiang J,Li H, Pan B, Chang J, He Y, He T, Strand R, Shi Y, Dong W. (2018)Penetration and Bactericidal Efficacy of Two Oral Care Products in anOral Biofilm Model. Am J Dent, Vol. 31, Issue 1: 53-60)

Results: Subjects are treated with the Inventive Ex. 3 (i.e., Sn+2.00%Citrulline), Ex. 5 (i.e., Sn+8.00% Citrulline), Comparative Ex. 8 (i.e.,Sn only), and the Control Ex. PBS as negative control. The results areprovided in Table 3.

TABLE 3 Active Penetration Rate in Biofilm Sn Co-localization Rate (%)Inventive Ex. 3 48.8 Inventive Ex. 5 45.3 Comparative Ex. 8 25.7 ControlEx. (PBS) 0

The results demonstrate the markedly higher stannous co-localizationpercentage with the Inventive Ex. 3 (48.8%), and Inventive Ex. 5 (45.3%)over the Comparative Ex. 8 (25.7%) and the control Ex. PBS (0%). Ineffect this data supports the improved penetration of the stannous ioninto the biofilms when combined with citrulline over the comparativeexamples without citrulline.

In yet another comparison, subjects are treated with the Inventive Ex. 2(i.e., Sn+2.00% Citrulline, free of Zinc source), Ex. 3 (i.e., Sn+2.00%Citrulline+0.533 wt % Zinc Citrate), Ex. 7 (i.e., Sn+2.00%Citrulline+1.160 wt % Zinc Citrate). The results are provided in Table4, also including the Control Ex. PBS as negative control.

TABLE 4 Active Penetration Rate in Biofilm Sn Co-localization Rate (%)Composition Ex. 2 70.1 Composition Ex. 3 48.8 Composition Ex. 7 23.9Control Ex. (PBS) 0

The results demonstrate that the stannous co-localization percentagewith the Composition Ex. 2 (70.1%), is higher than that of CompositionEx. 3 (48.8%), which in turn higher than that of Composition Ex. 7(23.9%) and the Control Ex. PBS (0%). In effect this data supports theimproved penetration of the stannous ion into the biofilms when combinedwith no Zinc or low level soluble Zinc (i.e., 0.533wt. %) over theExample with high level soluble Zinc (i.e., 1.160 wt. % or higher).

Example C.—Assay for Measuring Improved Wound Healing of Human GingivalFibroblasts

In-vitro human gingival fibroblasts are used to assess the effects ofwound healing migration as a result of treatment with InventiveCompositions and Comparative Compositions. The method involves threestages:

Stage 1—Culturing Primary Human Gingival Fibroblasts (“HGF”)

Human gingival fibroblasts are collected from tooth extraction patientsand washed with 5 mL of phosphate buffered saline (PBS). The tissues arechopped into small pieces and placed into 15 mL centrifuge tube. Thesamples are digested with equal amounts of 1 mL 8% dispase and 1 mL 6%collagenase for 1 hr at 37 ° C., during which time the samples need tobe shaken every 15 minutes. Once the digestion process is complete, thetube is centrifuged at 1100 RPM for 6 minutes at room temperature. Aftercentrifugation, a pellet of cells is formed in the bottom of the tubeseparating them from the supernatant solution. Then the supernatant isdiscarded and the cell pellet is suspended in 3 mL of fresh MinimumEssential Medium (“MEM”, available from Thermo Fisher) culture mediathen transferred to a petri dish. The petri dish with cells are placedin the incubator at 37° C. with 5% CO₂ for about 10 days. The petri dishis checked for changes in media color every two days. Fresh culturemedia is replaced if changes in media color occurred.

Stage 2—Sub-Culturing Human Gingival Fibroblast

When there is 80-90% cell monolayer coverage of the petri dish, then thepresent culture media is removed and washed with 5 mL of PBS. 1 mL 0.25%trypsin-EDTA solution is added and the cells sit for about 1-2 minutesat 37 ° C. until the cells are visibly round-shaped. It may be necessaryto tap the petri dish to remove any sticky cells from the petri dishsurface. At least 1 mL of fresh MEM culture media is added to inactivatethe trypsin and the cells are collected into a 15 mL centrifuge tube.The tube is then centrifuged at 1100 RPM for 6 minutes at roomtemperature. The supernatant is discarded and cell pellet isre-suspended in 4 mL of fresh MEM culture media in the same centrifugetube. 4 petri dishes are each placed with 1 mL cell suspension and 9 mLfresh MEM culture media in the incubator at 37° C. with 5% CO2 for about3-5 days until 80-90% cell monolayer coverage on the petri dishes areobserved. This stage should be repeated 2-4 times before the woundhealing assay to achieve the highest cell viability.

Stage 3—Wound Healing Assay

When there is 80-90% cell monolayer coverage on the petri dishes, thepresent culture media is removed and washed with 5 mL of PBS. 1 mL 0.25%trypsin-EDTA solution is added and the cells sit for about 1-2 minute at37° C. until the cells are visibly round-shaped. It may be necessary totap the culture petri dish to remove any sticky cells from the petridish surface. At least 1 mL of fresh MEM culture media is added toinactivate the trypsin and the cells are collected into a 15 mLcentrifuge tube. The tube is then centrifuged at 1100 RPM for 6 minutesat room temperature. The supernatant is discarded and cell pellet isre-suspended in 6 mL of fresh MEM culture media. 1 mL cell suspensionand 1 mL fresh MEM culture media are respectively added into each wellof a 6-well plate. The plates are incubated at 37° C. with 5% CO₂ until50-70% cell monolayer coverage is formed. The outer bottoms of wells arethen marked with a line in middle as the reference line during imageacquisition. A wound is created manually by scraping the right half ofcell monolayer with a sterilized 1 mL pipette tip. The cells are washedwith 2 mL PBS to remove any suspended cells until no suspended cells arevisible. 2 mL culture media, and 2 ml culture media containing 1%Comparative Compositions or 2 mL culture media containing 1% InventiveCompositions are added to the wells.

High density digital images of the HGF are captured with an Olympus®IX71 digital SLR camera with an Olympus® UIS2 WHN10× objective lens. Thefirst images are acquired at time 0 hr (i.e., Baseline) by using themiddle line markings on the plates as a reference line. The plates arethen incubated at 37° C. with 5% CO₂ for varying time intervals asdescribed below. The matched photographed region is acquired aspreviously, and images are acquired at later time intervals (e.g., 24hrs, 48 hr, 72 hrs, etc.) after baseline to assess the cell coverage (%)as an indication of the wound healing performance under the differenttreatment legs. Images are evaluated by Wimasis® WimScratch software(available from Wimasis GmbH, Germany) to determine the degree (i.e.,percentage) of HGF cell coverage (i.e., wound healing) pass the markedwound boundary, as compared to the matching baseline image for eachsample. WimScratch software utilizes advanced edge detection and overlaytechniques to recognize cells and blank area, i.e. the green overlay inthe image represents the cell-covered area of the particular image andthe grey area represents the wound area. The readout is presented forboth area and is normalized as percent of total area.

Results: With reference to Table 5 below, the results show that theInventive Composition Ex. 3 containing 2.00% Citrulline effectivelyimproves the wound healing though increased cell coverage (i.e.12.60%=62.60% total coverage−50.00% baseline) post the marked woundborder in baseline relative to the lower cell coverage (8.00%=58.00%total coverage−50.00% baseline) for the Human Gingival Fibroblaststreated with the Comparative Composition Ex. 8 without Citrulline.

TABLE 5 Wound Healing Increase at 24 hrs, 48 hrs, 72 hrs Post-Treatment24 h 48 h 72 h Inventive Composition Ex. 3 12.60% 16.28% 20.25%Comparative Composition Ex. 8  8.00% 10.40% 13.20%

Example D.—Discoloration in Accelerated Stability

Inventive Composition Ex. 3 (i.e., Sn+2.00% Citrulline, pH 6.0), Ex. 4(i.e., Sn+2.00% Citrulline, pH 7.0), Comparative Composition Ex. 10(i.e., Sn+2.00% Citrulline, pH 7.3) are statically kept in acceleratedstability chamber at 60° C. and avoided from light for 2 weeks. Theyellowness is visually examined by a group of qualified gradersaccording to below grading scales:

− Colorless + Slightly Yellow ++ Moderately Acceptable Yellow +++Obviously Yellow

Results: With reference to Table 6 below, the results show that theInventive Composition Ex. 3 (i.e., Sn+2.00% Citrulline, pH 6.5) and Ex.4 (i.e., Sn+2.00% Citrulline, pH 7.0) markedly reduce and/or retarddiscoloration (i.e. turning yellow to brown) in accelerated stabilitythan Comparative Composition Ex. 10 (i.e., Sn+2.00% Citrulline, pH 7.3).

TABLE 6 Yellowness Grading at Baseline, 1 Week and 2 Weeks inAccelerated Stability 1 Week at 2 Weeks at Baseline 60° C. 60° C.Inventive Ex. 3 − − + Inventive Ex. 4 − − ++ Comparative Ex. 10 − ++ +++

Example E.—Mouth Rinse Compositions

Mouth rinse compositions according to the present invention are shownbelow as Examples 12-15 in Table 7. These compositions contain astannous ion source and Citrulline. Preferably, these compositionsexhibit improved Gum Health benefits versus commercially availableformulations without these ingredients.

TABLE 7 Mouth Rinse Formulations Amount (Wt. %) Ingredients Ex.12 Ex. 13Ex. 14 Ex. 15 Glycerin 5.000 5.000 5.000% 5.000 Stannous ChlorideDihydrate 0.116 0.116 0.116 0.116 Citrulline 0.500 1.000 2.000 8.000Sucralose 0.030 0.030 0.030 0.030 Ethanol 5.000 5.000 5.000 5.000 MethylParaben 0.020 0.020 0.020 0.020 Propyl Paraben 0.005 0.005 0.005 0.005Flavor/sensate oils 0.100 0.100 0.100 0.100 Performathox 490 0.050 0.0500.050 0.050 Water q.s. q.s. q.s. q.s. Total 100% 100%   100% 100% TargetpH 6 6 6 6

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm ”

Every document cited herein, including any cross referenced or relatedpatent or application and any patent application or patent to which thisapplication claims priority or benefit thereof, is hereby incorporatedherein by reference in its entirety unless expressly excluded orotherwise limited. The citation of any document is not an admission thatit is prior art with respect to any invention disclosed or claimedherein or that it alone, or in any combination with any other referenceor references, teaches, suggests or discloses any such invention.Further, to the extent that any meaning or definition of a term in thisdocument conflicts with any meaning or definition of the same term in adocument incorporated by reference, the meaning or definition assignedto that term in this document shall govern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A dentifrice composition comprising: a) stannousion source; b) citrulline in free or salt form; and c) abrasive, whereinthe dentifrice composition has a pH of 7.2 or less.
 2. The dentifricecomposition of claim 1, wherein the dentifrice composition has a pH offrom 5.0 to 7.0.
 3. The dentifrice composition of claim 1, wherein thedentifrice composition comprises from 0.01% to 15%, by weight of thecomposition, of citrulline.
 4. The dentifrice composition of claim 1,wherein the stannous ion source comprises stannous chloride, stannousfluoride, or combinations thereof.
 5. The dentifrice composition ofclaim 4, wherein the dentifrice composition comprises a fluoride ionsource.
 6. The dentifrice composition of claim 5, wherein the dentifricecomposition comprises stannous fluoride.
 7. The dentifrice compositionof claim 5, wherein the fluoride ion source comprises sodium fluoride,sodium monofluorophosphate, indium fluoride, amine fluoride, potassiumfluoride, zinc fluoride, or combinations thereof, and the stannous ionsource comprises stannous chloride.
 8. The dentifrice composition ofclaim 1, wherein the composition comprises a zinc ion source.
 9. Thedentifrice composition of claim 8, wherein the zinc ion source comprisesfrom zinc citrate, zinc chloride, zinc sulfate, zinc gluconate, zinclactate, zinc phosphate, zinc oxide, or combinations thereof.
 10. Thedentifrice composition of claim 1, wherein the dentifrice compositioncomprises a thickening agent.
 11. The dentifrice composition of claim10, wherein the dentifrice composition comprises from 0.01% to 5%, byweight of the composition.
 12. The dentifrice composition of claim 11,wherein the thickening agent comprises thickening silica, a chargedcarboxymethyl cellulose, a non-ionic cellulose derivative, a linearsulfated polysaccharide, a natural gum, polymers comprising at least apolycarboxylated ethylene backbone, or combinations thereof.
 13. Thedentifrice composition of claim 12, wherein the linear sulfatepolysaccharide comprises Kappa-carrageenan, Iota-carrageenan,Lambda-carrageenan, or. combinations thereof.
 14. The dentifricecomposition of claim 12, wherein the natural gum comprises gum karaya,gum arabic, gum tragacanth, xanthan gum, or combination thereof.
 15. Thedentifrice composition of claim 1, wherein the dentifrice compositioncomprises a calcium-containing abrasive, a silica abrasive, orcombinations thereof.
 16. The dentifrice composition of claim 15,wherein the calcium-containing abrasive comprises calcium carbonate,dicalcium phosphate, tricalcium phosphate, calcium orthophosphate,calcium metaphosphate, calcium polyphosphate, calcium oxyapatite, sodiumcarbonate, sodium bicarbonate, or combinations thereof.